My original engagement ring diamond from my first husband was .2 carat. I had that made in to a ring after the divorce, then lost the ring. That's the only piece of jewelry I've ever misplaced. Karma? My second (and present) marriage - the first diamond was about a carat, then to 1.5 carats, now a little over 2.5 carats. That's as high as I want to go - anything larger looks out-of-proportion and kind of gaudy on my hand.
Having posted this just a few weeks ago, the stone shrunk as someone had mentioned, and so I pumped it up to a 3.20 carat. Hopefully this one won't shrink like the last one did!